Stretch yarn



Feb. 14, 1961 R. BOUVET STRETCH YARN Filed May 4, 1956 STRETCHYARN RenBouvet, Drexel Park, Pa., assignor to American Viscose Corporation,Philadelphia, Pa., a corporation of Delaware Filed May 4, 1956, Ser. No.582,740

2 Claims. (Cl. 57-140) The present invention relates to anew and noveltype stretch yarn.

In particular, the invention relates to a yarn similar to that type nowused in producing stretch articles of wearing apparel such as stretchsocks for men, stretch stockings for Women, etc. These stretch articlesare produced and sold without reference to a particular numerical sizeof the article since the stretchable characteristic of the items makesit possible to accommodate a wide range of numerical sizes.

It is one object of my invention to provide a novel and improvedcomposite stretch yarn.

Another object of my invention is to provide a novel and. improvedcomposite stretch yarn which has the appearance, uniformity and feel ofspun yarn.

Still another object of my invention is to provide a novel and improvedcomposite stretch yarn which is less expensive than the stretch yarnsnow on the market.

A further object of my invention is to provide a novel and improvedcomposite stretch yarn wherein only a portion of the total yarn weightcomprises yarn of a stretchable nature.

A final object of my invention is to provide a novel and improved methodfor producing the composite stretch yarn of the above objects.

Other objects and advantagesof my invention will be come more apparentfrom a study of the following description and drawing. wherein:

Figurel shows a length of the core yarn of my composite stretch yarn;

Figure 2 shows the core yarn of my composite stretch yarn after apermanent crimp has been formed therein;

Figure 3 is a diagrammatic view showing an apparatus for. applying afibrous covering of. non-stretchable nature to the crimped and tensionedcore yarn;

Figure 4 is a detail of a portion of. the apparatus of Figure 3 Figure 5shows the composite stretch yarn in a stretched or tensioned state afterthe crimped core yarn has been covered or plated with a fibrous coveringof non-stretchable nature; and

Figure 6 shows my composite stretch yarn including the crimped core andcovering in its relaxed state.

Briefly, my composite stretch yarn consists of a core portion of crimpedthermosensitive organic plastic fibers or'filaments which have thatproperty known as a plastic memory, and a fibrous covering for the coreyarn portion which covering is formed of non-stretchable fibers.

The crimped thermosensitive core fibers or filaments comprise at leastby weight of the total composite yarn weight.

The term plastic memory, as used in this specification and claims,designates the property of a fiber.

r i i erty are made by heating or crimping the fiber by mechanical meansor the like and subjecting the fiber while in the crimp form to heatsufiicient to set the fiber in the crimp form. When the fiber issubjected to tension, it will straighten out and the crimp will beremoved. However, upon releasing the tension, the yarn will return toits crimp form. This crimping is unafiected by moisture, water or thelike.

A novel method is provided for producing the composite stretch yarn. Incarrying out the method, the core yarns or fibers first undergo acrimping operation whereby a permanent crimp is set Within the coreyarns or fibers. The crimped core is then stretched a sufficient amountto straighten out the crimp in the yarn after which a fibrous coveringof non-stretchable nature is then applied to the core portion. When thetension applied to the core yarn is relleased, the composite yarn willassume a crimped form in view of the return of the core yarn to itsoriginal crimp form.

Referring now to Figure 1 of the drawing, there is shown the core yarnor portion 2 of my composite stretch yarn. The core 2 is shown in itsnatural or noncrimped state. The core portion of my composite stretchyarn consists of certain type plastic organic continuous filaments or itmay be a fibrous spun yarn consisting of certain type plastic organicstaple fibers. For purposes of my invention, the core filaments orfibers comprise those organic plastic fibers or filaments which exhibitthe phenomenon known as a plastic memory." Such fibers and filaments canbe formed only from a limited class of certain organic plasticthermosensitive materials. Among these plastic memory yarns are those ofthe acrylic fiber class which are formed from polymers and copolymers ofacrylonitrile and are sold commercially under the names of Acrilan,dynel or Darvan. Dacron, a polyester fiber, which is produced] from achemical composition of ethylene glycol and terephthalic acid, has alsobeen found satisfactory for my purpose. Nylon, generally formed fromdiamines and dicarboxylic acids (adipic acid), has been found to beextremely successful when used as a core yarn for my composite stretchyarn. As mentioned above, one common property of these yarns is thatwhen heated to certain temperatures, they may be reshaped as desired.Upon cooling, the reshaped contour is permanently set in the yarn.Another property common to these type yarns is that they all have thatproperty known as a plastic memory as defined above.

Figure 2 shows the core yarn 2 in crimped condition after it has beendischarged from the crimping and crimpsetting apparatus or station 4.There are several known and accepted methods and apparatus now in usefor crimping and setting such yarns formed from the materials listedabove. A few of these known methods are the Helanca, Ban-Lon, Agilon,and the Flufion methods. All of these methods generally involve thesteps of heating the thermosensitive filaments or fibers to a desiredtemperature at which temperature the shape or physical structure of thefilaments may be altered and permanently set in crimped form.

A fibrous covering is applied to the crimped core 2, preferably by theapparatus and method shown in Figure 3. Since, as mentioned above, thecovering for the core 2 is formed of fibrous material, the compositestretch yarn has the feel and character of a spun yarn. As seen inFigure 3, a pair of fibrous rovings (continuous bundles of staplefibers) 6, 6 are drawn from separate supply sources (not shown). Theyare brought together in a side-by-side, spaced-apart, parallelrelation-\ ship by a double trumpet guide 8 which is secured to a crossbar 10 which is in turn afiixed to a support 12. The rovings 6, 6 arecarried through a series of drawing the cover.

weight.

ing rolls, generally designated as 14, 16 and 18 whereby the rovings 6,6 are spun. These rollers maintain the rovings in their side-by-side,spaced-apart, parallel relation ship. The journals and driving means forthe drawing rolls are not shown since they do not constitute a part ofthe present invention. The crimped core yarn 2 is fed from a supplysource (not shown), over a tension device 20 which may consist of a pairof opposing and cooperating discs. The tension device 20 temporarilyremoves the crimp from the core 2 so that it may be more efli cientlyand thoroughly incorporated into the rovings 6, 6. The core 2, in itsnon-crimped condition, then passes through an eye guide 22 formed in theend of an overhanging arm 24 afiixed to the cross bar 10. The eye guide22 lies just to the rear of the draw rolls 18 and is so aligned with therolls 18 that it conducts the core yarn 2 to the rolls 18 between therovings 6, 6 at a paint equidistant from each roving 6. The feeding andpositioning of the core yarn 2 between the rovings 6, 6 is shown moreclearly in Figure 4. It is extremely important that the core yarn 2 befed between the rovings at a point exactly between the two rovings oflarger bulk (equidistant from the two rovings) so that when the core 2and the rovings 6, 6 are twisted together after they emerge from therollers 18' (see Figure 3) to form the composite yarn B, the core 2 willbe embedded, so to speak, in the rovings 6, 6. By twisting the rovings6, 6 and core yarn 2 after they emerge from the rolls 18, 18, therovings and core are incorporated into a unitary structure which isfirmly held together. The

thickness of the rovings 6, 6 and the corn yarn 2 may be varied asdesired to produce whatever denier composite yarn is desired. The finalcomposite yarn B preferably has a twist of one to three turns per inch.However, as many turns per inch as desired may be incorporated in thecomposite yarn.

The cover rovings 6, 6 comprise continuous bundles of staple fiberswhich are of a non-elastic or non-stretchable nature. Many types offibers may be used in form- Among those found desirable are the purecellulosic fibers such as cotton, the regenerated cellulose fibers suchas viscose rayon, cellulose acetate, etc. and other types of fibers.

Figure 5 .shows the composite stretch yarn B in its stretched ortensioned condition. As seen therein, the

Figure 6 shows the composite stretchyarn B in its relaxed position. Asseen therein, the core or plastic memory yarn 2 has reassumed itsoriginally set crimped form since it tends to turn to its original formonce the stretch tension applied to the yarn has been released.

bright viscose rayon. .After testing, it was found that.

the socks extended 60% from their relaxed condition and that the elasticrecovery was complete. With such an extensive range of stretch, agenerous margin is provided for whereby the sock producers may eliminatethe old practice of producing different size socks.

There are, of course, many'recognized uses for stretch yarns of thisnature other than the mens socks mentioned above. All manner ofsnug-fitting garments may be produced from my composite yarn. Stretchsweaters, having the feel and appearance of sweaters formed from spunyarn, may also be produced.

There are several advantages found with my stretch type yarn which arenot inherent with other types of stretch yarns on the market. The mainadvantage is that only a fairly low percentage of the expensive core orstretchable yarn is required. The remainder of the yarn may be made upof less expensive material. Garments produced from my stretch yarn couldeasily, retail at lower prices than those on the market today. Sinceonly a fairly low percentage of the total yarn weight is subjected tothe crimping treatment, which is rather an expensive operation, a greatsaving is provided in the total cost of the yarn production. Inaddition, my stretch yarn has the feel and appearance of spun yarn whichis a highly desirable feature with apparel producers today. The fibrouscovering is of a hydrophilic nature whereby better absorption ofmoisture is effected which adds to the comfort of the wearer. It isfurther evident that the composite yarn may be uniformly dyed since thecon volutions of the cover rovings are positioned on the core 'core 2 iscompletely embedded in the rovings 6, 6 and p is uniformly covered bythe rovings.

The convolutions of the cover rovings 6, 6 are close enough to oneanother so that a complete uninterrupted fibrous cover is formed aroundthe stretchable core 2 when in either a relaxed or stretched condition.

The weight of the core yarn with respect to the total weight of thecomposite yarn may be varied to produce composite yarn of desiredstretch ranges and strength. Satisfactory composite stretch yarns havebeen formed by using core yarn portions which comprise 15 to of void ofany practicable stretch ability.

Men's socks were produced with my composite yarn wherein a core yarn ofnylon filaments constituted 25% of the total weight of the yarn. Theremaining 75% of the yarn weight constituted a fibrous roving cover ofyarn in close relationship whereby complete coverage is provided in boththe relaxed and stretch state of the yarn.

It is to be understood that changes and variations may be made withoutdeparting from the spirit and scope of the present invention as definedin the appended claims.

I claim:

1. A method of producing a composite stretch-type yarn comprisingfeeding a pair of fibrous rovings of nonstretchable nature in a sideby-side, spaced-apart, parallel relationship to a twisting station,feeding a crimped core yarn having a plastic memory between the rovingsat a point equidistant from each roving, drafting the rovings as theyare fed to the twisting station, tensioning the crimped yarn prior toits introduction between the rev ings to temporarily remove the crimpfrom the yarn, twisting the drafted rovings and the yarn together, andrelaxing the tensioned yarn so that the yarn and drafted rovings twistedtogether assume a crimped condition.

2.. A stretch-type composite yarn comprising a crimped thermosensitivemultifilament organic plastic core element, a fibrous covering aroundsaid core element, said covering comprising a pair of viscose rayonrovings wound around said core element so as to completely cover saidcore element in both its stretched and relaxed conditions, and saidcrimped core element comprising from 15% to 60% of the total yarnweight.

- References Cited in the file of this patent UNITED STATES PATENTSOTHER REFERENCES Textile World, June 1955. (Copy in Division 21.)

2. A STRETCH-TYPE COMPOSITE YARN COMPRISING A CRIMPED THERMOSENSITIVEMULTIFILAMENT ORGANIC PLASTIC CORE ELEMENT, A FIBROUS COVERING AROUNDSAID CORE ELEMENT, SAID COVERING COMPRISING A PAIR OF VISCOSE RAYONROVINGS WOUND AROUND SAID CORE ELEMENT SO AS TO COMPLETELY COVER SAIDCORE ELEMENT IN BOTH ITS STRETCHED AND RELAXED CONDITIONS, AND SAIDCRIMPED CORE ELEMENT COMPRISING FROM 15% TO 60% OF THE TOTAL YARNWEIGHT.